Oil in Distributor 1938 Buick Special

[Guest Ron Blalock]

My 1938 Buick special would not start last week. I found a thin coating of oil in the distributor on the points, condenser, and wires. Cleaned the points and it starts now. I found evidence of oil leakage out of the filler cap on the valve cover. Wiped it off and it has not returned after several long trips. I checked up the oil breather pipe and saw no visual blockage from underneath. The car performs as usual. Is there any insight to this that someone can add?

[Guest SteveAS]

Do you have a gasket sealing around the bottom edge of the distributor cap? If not, I'd guess that's how the film of oil got under the cap.

[Seldenguy]

Ron-- Sounds like it may have"wicked" up from the crankcase via the distributor drive shaft from the bevel gears. Or perhaps the crankcase breather may be partially plugged and causing a positive pressure in the lower end. I'm not that familiar with the '38 but the'36,s have a side plate breather and a draft tube on the same side and ahead of the distributor. I have never seen a gasket under the distibutor cap, they are designed to form a dry seal protected by the drop lip of the cap.--Bob

[Guest SteveAS]

I have never seen a gasket under the distibutor cap, they are designed to form a dry seal protected by the drop lip of the cap.--Bob

Hmmm . . . I could easily be wrong about a sealing ring around the base of the distributor cap!

I thought I saw a exploded diagram of the distributor at some point that showed a sealing ring. And my (recently acquired) '38 doesn't have a sealing ring, but there is some play in the cap even when it's snapped down, which made me think mine is missing its sealing ring.

[critterpainter]

Also a bad vacumn advance on a tired engine, the intake draws the oil up from the crankcase.

[Ben Bruce aka First Born]

Also a bad vacumn advance on a tired engine, the intake draws the oil up from the crankcase.

A real good possibility.

Ben

[Glassesguy]

Guys: Seems to me I recall a cork seal that fits into the crankcase boss into which the distributor fits. It is slightly cone shaped and is found under the casting on the distributor body that has the slots for the hold down bolts. I don't have the part # handy. If it's missing could this be a possibility?

[Guest Grant Magrath]

Actually, I seem to recall something like that to, now that you mention it Dave.

Cheers

Grant

[Patrick W. Brooks]

It is difficult to diagnose problems without seeing the situation. However, I can tell you that oil does get to the distributor as it is needed for lubrication of the bushings which the distributor rides on. This oil comes from a very small hole which is cast in the block at the top of the cast distributor base. Inside the block is a very small "cup" cast into the block which collects oil which is in the air in the turbulent interior engine. From this cup the oil passes through the hole previously mentioned into the distributor shaft and down into the bushings and finally drains into the oil pan. My personal opinion is that it is not unknown that a thin coating of oil collects as you describe as I have seen it myself, although it has not effected the operation of the engine. Usually the problem is that the oil hole has become plugged and will not let oil pass and the distributor bushings wear out. Many times I have used a piece of wire to reopen the hole after an engine has set for years without being operated as the oil solidifies and plugs the hole. I have even had to reopen the hole after an engine block has been in a caustic tank in preperation for engine rebuilding. These small details are important to proper engine operation and lubrication.

Cleaning the inside of the distributor was part of maintance and I am not sure I would let what you describe bother me.

Hope this helps. Patrick W. Brooks

[Glassesguy]

Guys: Seems to me I recall a cork seal that fits into the crankcase boss into which the distributor fits. It is slightly cone shaped and is found under the casting on the distributor body that has the slots for the hold down bolts. I don't have the part # handy. If it's missing could this be a possibility?

Found the number on this "packing". Gr. 2.363 # 1266536 fits all Series 40 from 1934 to 1953. Also fits the 320 engine from 1936 through 1952. Material is cork. Dimensions listed as 1 3/8 I.D. x 1 39/64 O.D.

[jeff]

Great suggestions. I like the plugged drain hole theory and the failed vacuum diaphragm theory, which would try to draw oil up into the top end of the distributor. Maybe a combination of both. I do think that the cork gasket is intended to keep oil from leaking to the outside world - you'll want to make up one of these, but I don't think it's your problem.

My suggestion is to pull the distributor (photograph and mark the distributor body location and the rotor location first!). Set the distributor in a vise, and then remove rotor, points, condensor AND breaker plate. Lifting the breaker plate will allow you to see the mechanical advance weights and springs. My assembly in this area was absolutely filthy and gummed up with rusty sludge. Again, photograph the location of the weights and springs, then carefully disassemble. Now you will be able to clean everything with a nice, healthy bath of kerosene. At this point you will understand how the lower end gets lubricated. Make sure the passageways are clean (engine block as well), then begin reassembly. Test the vacuum advance by connecting a vacuum source and observing what happens (or just suck on it!)(sorry, that didn't sound right!)

Good luck.